Floor cleaning in public, commercial, institutional and industrial buildings have led to the development of various specialized floor cleaning machines, such as hard and soft floor cleaning machines. These cleaning machines generally utilize a cleaning head that includes one or more cleaning tools configured to perform the desired cleaning operation on the floor surface. These cleaning machines include dedicated floor sweeping machines, dedicated floor scrubbing machines and combination floor sweeping and scrubbing machines.
An example of a dedicated hard floor sweeping and scrubbing machine is described in U.S. Pat. No. 5,901,407, which is assigned to Tennant Company of Minneapolis, Minn. and which is hereby incorporated by reference in its entirety. The machine uses a cleaning head having two cleaning tools in the form of cylindrical brushes. The cleaning tools counter-rotate in the directions indicated by the arrows shown. Water and detergent are sprayed on the floor ahead of the brushes so the brushes can scour the floor at the same time they are sweeping debris from the floor. A vacuum squeegee removes liquid waste from the floor during the wet scrubbing and sweeping operations. The cleaning tools engage each other such that debris on the floor is swept between the two cleaning tools and is directed into a waste hopper by a deflector.
An example of a dedicated floor sweeper is described in U.S. Pat. No. 4,571,771, which is assigned to Tennant Company of Minneapolis, Minn. and is hereby incorporated by reference in its entirety. The floor sweeper includes a cleaning head comprised of a rotating cylindrical brush that contacts the floor and throws loose debris into a hopper which is periodically emptied either manually or through a motorized lift. Combination floor sweeping and scrubbing machines were developed to avoid the necessity of having two machines. Some floor sweeping and scrubbing machines were created by mounting sweeping components to the front end of a dedicated scrubbing machine to making one large, multi-function machine.
Scrubbing systems are well known in the art. Scrubbing systems commonly include a driver assembly and a cleaning head that is a rotatable scrubber in the form of a brush, pad, or the like. A control device may be utilized for controlling the degree of scrubbing (typically a function of down-force applied through the scrubber) applied to a floor surface depending upon the type and/or condition of floor surface intended to be scrubbed. The scrubber driver assemblies for scrubbing systems are well known in the art and commonly include one or more rotatable brushes driven by a driver motor affixed to a scrubber head. Scrubber heads of the prior art include a lift mechanism that selectively raises and lowers the scrub heads by an actuator coupled to the driver so as to achieve an intended down force or scrubbing pressure of the scrub pad against a floor surface.
Some prior art scrub head lift mechanisms and suspensions have included a large number of parts, which can increase the cost and complexity of such mechanisms and suspensions. In addition, some prior art scrub head lift mechanisms and suspensions have a large footprint on the surface maintenance vehicle that can complicate packaging the scrub head lift mechanisms and suspensions within the confines of the vehicle. In addition, the packaging considerations of a relatively large scrub head lift mechanisms and suspensions make it difficult to use the same scrub head lift mechanisms and suspensions designs on different vehicles of different sizes.